Without limiting the scope of the invention, its background is described in connection with synthesis of N-Acetyl Cysteine Amide.
One such method is taught in U.S. Patent Publication No. 20170183302, filed by Warner, et al., entitled “Method for Preparation of N-Acetyl Cysteine Amide”. Briefly, these inventors teach an process for the preparation of N-acetyl-L-cysteine amide (NACA) starting with N-acetyl-L-cysteine that involves contacting N-acetyl-L-cysteine with an organic alcohol and an inorganic acid to form an organic solution containing N-acetyl-L-cysteine ester; neutralizing the acid in the organic solution with an aqueous solution containing a base to form a neutralized mixture; separating an organic solution containing N-acetyl-L-cysteine ester from the neutralized mixture; removing the N-acetyl-L-cysteine ester from the organic solution under reduced pressure; and contacting the N-acetyl-L-cysteine ester with ammonia.
Another such method for the preparation of N-acetyl cysteine amide (NACA) was previously described by Martin, et al., entitled “Amides of N-Acylcysteines as Mucolytic Agents”, J. Med. Chem. 1967, 10, 1172-1176.
However, a need remains for developing an efficient method for the effective, large-scale synthesis of N-acetyl cysteine amide that provides the product in high chemical yields and, in particular, high chemical and enantiomeric purity, without the need for chromatography.